Re: [pulseaudio-discuss] Why is it still hissing?
On Tue, May 24, 2011 at 10:04 AM, David Henningsson david.hennings...@canonical.com wrote: Ok, so there is still a high-pitched noise with 5.1, although I tried to fix that a while ago. I now know what the error is, but perhaps somewhat with more GCC-ASM skills can help me fix it. I spent parts of yesterday and today analysing it and came up with the following conclusion: Here's the asm code as written in svolume_sse.c, function pa_volume_s16ne_sse2: #define MOD_ADD(a,b) \ add #a, %3 \n\t /* channel += inc */ \ mov %3, %4 \n\t \ sub #b, %4 \n\t /* tmp = channel - channels */ \ cmovae %4, %3 \n\t /* if (tmp = 0) channel = tmp */ And called with: MOD_ADD($8, %5) Here's what it shows up with gdb (on i386) : 0x00f3fbe6 +550: add $0x8,%edi 0x00f3fbe9 +553: mov %edi,%ecx 0x00f3fbeb +555: sub %edi,%ecx 0x00f3fbed +557: cmovae %ecx,%edi The error: both %3 and %5 is turned into the %edi register. Here's the register allocation: : +r (samples), +r (volumes), +r (length), =D (channel), =r (temp) : rm ((pa_reg_x86)channels) : cc As I can tell from the above the =D forces %3 to go into %edi, but I don't know how to tell GCC not to use %edi for %5 (channels) as well, does anybody know? Can this be a GCC bug? Either use +D for channel or rm for channels. The manual here: http://gcc.gnu.org/onlinedocs/gcc/Modifiers.html#Modifiers is pretty good. --Andy ___ pulseaudio-discuss mailing list pulseaudio-discuss@mail.0pointer.de https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss
[pulseaudio-discuss] Why is it still hissing?
Ok, so there is still a high-pitched noise with 5.1, although I tried to fix that a while ago. I now know what the error is, but perhaps somewhat with more GCC-ASM skills can help me fix it. I spent parts of yesterday and today analysing it and came up with the following conclusion: Here's the asm code as written in svolume_sse.c, function pa_volume_s16ne_sse2: #define MOD_ADD(a,b) \ add #a, %3 \n\t /* channel += inc */ \ mov %3, %4 \n\t\ sub #b, %4 \n\t /* tmp = channel - channels */ \ cmovae %4, %3 \n\t /* if (tmp = 0) channel = tmp */ And called with: MOD_ADD($8, %5) Here's what it shows up with gdb (on i386) : 0x00f3fbe6 +550: add$0x8,%edi 0x00f3fbe9 +553: mov%edi,%ecx 0x00f3fbeb +555: sub%edi,%ecx 0x00f3fbed +557: cmovae %ecx,%edi The error: both %3 and %5 is turned into the %edi register. Here's the register allocation: : +r (samples), +r (volumes), +r (length), =D (channel), =r (temp) : rm ((pa_reg_x86)channels) : cc As I can tell from the above the =D forces %3 to go into %edi, but I don't know how to tell GCC not to use %edi for %5 (channels) as well, does anybody know? Can this be a GCC bug? (Btw, based on this analysis, I'm guessing that my former fix fixed the problem for amd64, but not i386.) -- David Henningsson, Canonical Ltd. http://launchpad.net/~diwic ___ pulseaudio-discuss mailing list pulseaudio-discuss@mail.0pointer.de https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss
Re: [pulseaudio-discuss] Why is it still hissing?
'Twas brillig, and David Henningsson at 24/05/11 15:04 did gyre and gimble: (Btw, based on this analysis, I'm guessing that my former fix fixed the problem for amd64, but not i386.) This could be correct as when we inspected this error at my house, the server actually doing the output was indeed i386, even if my machine is x86_64... Cheers for hunting this down :D Col -- Colin Guthrie gmane(at)colin.guthr.ie http://colin.guthr.ie/ Day Job: Tribalogic Limited [http://www.tribalogic.net/] Open Source: Mageia Contributor [http://www.mageia.org/] PulseAudio Hacker [http://www.pulseaudio.org/] Trac Hacker [http://trac.edgewall.org/] ___ pulseaudio-discuss mailing list pulseaudio-discuss@mail.0pointer.de https://tango.0pointer.de/mailman/listinfo/pulseaudio-discuss
